In an exhaust gas turbocharger, the bearing housing connects a compressor housing for compressing the air flowing to combustion chambers of the combustion cylinder with a turbine housing for driving a shaft by means of an exhaust gas flow. The bearing housing, the compressor housing and the turbine housing are connected to one another by the shaft. The turbine housing and the compressor housing are charged with a particle flow and have to be separated from the lubricating oil accommodating bearing housing in an oil-tight manner.
The bearing housing is separated from the compressor housing by the bearing housing cover. In order for the shaft to be able to connect the bearing housing with the compressor housing, the bearing housing cover has a rotation-symmetrical seal recess with a centre axis. In the seal recess, a sealing bush is arranged at least in regions, which sealing bush comprises a shaft recess for the shaft and seals the same relative to the compressor housing. The sealing bush is arranged on a locating surface of the bearing housing cover with a stop surface and is thereby axially fixed in the direction of the compressor housing. On the locating surface of the bearing housing cover, a circumferential groove that is spaced from the centre axis is additionally arranged.
At high rotational speeds, an overpressure is present in the compressor housing compared with the bearing housing so that the lubricating oil cannot escape from the bearing housing into the compressor housing. However, when the rotational speed and thus the pressure in the compressor housing drops, the lubricating oil can escape into the compressor housing, in particular between the locating surface of the bearing housing and the stop surface of the sealing bush.
From the prior art, some solutions for an oil-tight separation of the bearing housing from the compressor housing are already known. Accordingly, the publications JP 721 441 A and U.S. Pat. No. 4,664,605 A for example describe additional sealing washers by way of which the lubricating oil is already caught before the bearing housing cover and conducted back into an interior space of the bearing housing. However, if the lubricating oil enters between the sealing washer and the bearing housing cover the lubricating oil can no longer be caught.
The publication EP 2 192 272 B1 describes a further solution to the problem described above.